There is a known sensor that identifies a size and a speed of an object, a distance of the object from a sensor, and the like by utilizing reflection light returned from a detection object by irradiating the object with the laser light (see Patent Literatures 1 and 2). The sensor is covered with an exterior component for protection, and the exterior component is provided with an optical window that transmits light in a wavelength band of laser to be emitted in order to: make projected light beams be emitted to the object located outside from a laser light source located inside; and make the reflection light from the detection object enter a light receiver located inside. In Patent Literatures 1 and 2, an optical window main body and components other than the optical window are separately manufactured, and the exterior component for the sensor is obtained by joining these components.
When the exterior component is manufactured by the above-described method, there are problems in accuracy of the optical window, dustproof and waterproof properties of the exterior component, weight reduction, and miniaturization. First, as for the accuracy of the optical window, in a case where the optical window has a curved surface, there is a problem that a manufacturing error such as a shape error at the time of bending processing and a thickness error at the time of injection molding are likely to occur. Additionally, when the optical window is joined to a component to which the optical window is to be attached by using an adhesive or the like, there is a problem that the surface shape of the optical window is likely to be distorted by stress. Thus, when accuracy of the optical window is not good, a light amount is reduced because the laser cannot be projected and received at an aimed place, and there is a possibility that detection accuracy is seriously deteriorated, especially on a long-distance side. Additionally, as for the dustproof and waterproof properties, in a case where the optical window is made of a resin and a component to which the optical window is to be attached is made of a metal, there is a problem that a joined part is easily peeled off due to a difference in linear expansion, and dust and moisture intrude in the inside at the time of environment change such as change of a temperature or the like. Furthermore, as for the weight reduction and miniaturization, restrictions are imposed on matters such as components to be joined and a joining range in view of securing strength and the like, and there may be a problem that application to a compact moving body such as a drone becomes difficult.